1. Field of the Invention
The present invention relates to a flow amount adjusting valve, which enables adjustment of a flow amount of a pressure fluid under an opening/closing operation of a valve.
2. Description of the Related Art
Heretofore, a flow amount adjusting valve has been known, in which a conical valve plug is moveably disposed inside of a body equipped with a passage therein through which fluid flows, and wherein a flow amount of the fluid that flows through a gap between the valve plug and a valve seat is adjustable by causing the valve plug to approach and separate away from a valve seat which faces the flow passage.
In such a flow amount adjusting valve, for example as disclosed in Japanese Laid-Open Patent Publication No. 11-230407, an operating element is provided for displacing the valve plug. The valve plug is displaced in an axial direction by an operator turning the operating element, whereby the flow amount of a desired fluid is adjusted by causing the valve plug to approach and separate away from the valve seat.
However, in the aforementioned conventional technique, when a needle valve that forms the valve plug is displaced along the axial direction, because a function is not provided that allows the displacement amount (movement amount) of the valve plug to be confirmed visually from the outside, it is difficult and troublesome for the flow amount of the fluid, which is adjusted by displacement of the needle valve, to be adjusted with high accuracy. Further, in the event that a plurality of such flow amount adjusting valves are used simultaneously, it is necessary to adjust flow amounts while performing measurements on each of the flow amount adjusting valves respectively, such that the adjustment operation becomes extremely cumbersome.